Generally all the gaseous fuel burners and all their mixtures (e.g. natural gas, LP gas, hydrogen, etc.) have the same application, that is to burn a gaseous fuel (including all mixtures thereof) to generate heat. However most show low energy efficiency since the combustion processes are low efficient and consume high quantities of fuel, combined with high pollutant emissions of NOx, CO and CO2.
Moreover conventional burners perform the combustion process outside the burner which lowers their efficiency in the heat transfer process. The general structural configuration of this burners produces a mix of the gaseous fuel (including all mixtures thereof) and the oxidant in a laminar flow or hardly reaching the turbulent flow, which is not sufficient to excite the gas flow to liberate its maximum energy.
A search of precedents to establish the state of the art found the the international patent application No. WO2008007016 by De Smedt Guillaume submitted on Jul. 10, 2007 which claims the French priority FR0652974 of Jul. 13, 2006, which has been submitted in Mexico and granted the number MX297397. That patent protects a combustion method for a fuel using an oxidant and at least one mainly inert gas, whereby the fuel and oxidant are injected in such way it produces a flame. The inert gas is mainly injected in the form of two nozzles in such way that the first nozzle surrounds the flame created by the fuel and the oxidant and has a divergent swirl in respect to the flame; the second nozzle surrounds the first nozzle with inert gas mainly and has a convergent swirl in respect to the flame created by the fuel and the oxidant. The invention also relates to a suitable burner to implement the method. The burner features at least one means to inject fuel and at least one means to inject the oxidant in such fashion they produce a flame; two means to inject inert gas, the first means injects part of the inert gas in the form of a nozzle that surrounds the flame produced by the oxidant and the fuel and consists of a suitable means to produce a divergent swirl of the inert gas flow which mainly passes through it; the second means to inject inert gas in the form of a nozzle which surrounds the inert gas nozzle of the first medium to inject inert gas and the second medium to inject inert gas consists of a suitable medium to produce a convergent swirl of the inert gas flow which passes through it.
However this burner is configured to generate a first combustion of a mixture of a gaseous fuel with an oxidant (air) and re-inject residual gas produced by the combustion to compensate for the absence of nitrogen. Although it prevents a high production of NOx, the configuration and geometric arrangement of the burner is such that it does not allow a more efficient combustion which translates to a higher energy efficiency, in addition the low injection speed of residual gas used increases the size of the boiler and poses greater safety issues.
The search also found the American patent application US2007/0072141 by Marco Daneri et al. which discloses a low pollutant emission gas burner which consists of a metallic main body (6), an inner lancet (11) for gas fuel, at least two outer lancets (10) for gas fuel, an individual duct (8) to transport preheated air, a regulation system for the gas fuel, a refractory unit (30), characterized by a gas nozzle (1) which consists of a series of nozzles (20) to inject the preheated air in the combustion chamber in which, when operating the gas regulation system, it is possible to change with continuity, from an operational mode of the burner with flame to flame-less operational mode, the latter characterized by low emissions of contaminant agents.
However said burner does not feature a structure or geometric arrangement which allows neither a more efficient combustion process, nor good energy efficiency; moreover it requires the injection of preheated air.
The search also found the American patent US6638058B1 by Sebastian Mainush et al. granted on Oct. 28, 2013, which protects a tubular burner for industrial ovens which consists of: An inner final section protruding in a combustion zone of the oven supplied with secondary combustion air; a variety of radially arranged tubular walls separated from each other and coaxially one inside the other, which limit a variety of separate, cross-section, approximately annular supply ducts for combustion gas and fuel; in which the front end, pointed towards the combustion zone of at least a supply duct essentially built to supply a combustion gas, is fitted with a number of individual nozzles distributed approximately in annular arrangement; wherein, in cross-section view from the final section of the inner burner, at least one outer annular supply duct is built essentially as a fuel supply duct and the gas supply duct fitted with the individual nozzles is placed radially within this fuel supply conduct.
However, the structural configuration and geometric arrangement of the burner prevents offering the characteristics and benefits provided by the gaseous fuel burner (including all mixtures thereof) of the invention.
The search also found the patent US778510081 of Malcolm Swanson and Michael Swanson of May 26, 2006, and granted on May 26, 2006 and on Aug. 31, 2010, which protects a burner assembly which includes a housing with an air inlet and burner end, an engine and a driver mounted in the housing. The driver is in fluid communication with the air inlet, in mechanic communication with the engine and adapted to direct the air from the air inlet towards the end of the burner of the housing. The assembly of the burner also includes a variety of gas injection pipes arranged substantially parallel amongst themselves. Each one of the variety of gas injection pipes includes an opening at the end of the pipe, an end of the outlet pipe and at least one opening. Moreover, the assembly of the burner includes a first layer of pipes arranged close to the inlet ends of the variety of gas injection pipes and a second layer of pipes arranged close to the outlet ends of the variety of injection gas pipes. The assembly of the burner includes also a turning fin with at least a layer of centrifuge pallets. The turning fin is mounted in the end of the burner of the housing and is adapted to direct the air flow in the end of the burner. The arrangement of the burner also includes an igniter mounted in the end of the burner of the house. The igniter is adapted to ignite the mixture of air and fuel in the end of the burner of the housing to produce the main flame.
However, the structural configuration and geometric arrangement of the burner also do not offer the benefits provided by the gaseous fuel burner (including all mixtures thereof) of the invention; moreover it shows that the flame is generated in the end part outside the burner.
The stoichiometric ratio of air-methane is 17:1 in mass. Since methane is 90% of the composition of natural gas, we can state that the majority of the conventional burners employ a methane-air ratio of 19:1 in mass; considering an excess of air of 15%. This ratios do not achieve fuel savings and the heated air mass is reduced; moreover the levels of pollutant emissions to the atmosphere are very high.
The need to improve the efficiency in the oxidation of fossil fuels becomes more and more important each day, since the energy costs increase while the natural reservoirs diminish; besides the alarming current environmental conditions. In view of the situation, the gaseous fuel burner (including all mixtures thereof) with high energy and combustion efficiency, low pollutant emissions and greater heat transfer which allows to heat a bigger air mass at higher temperatures has been developed.